How can this (math) be?

[Beestie]

Originally Posted by Happy Monkey

Not quite - the problem is that (a-b) is zero, and you are dividing by it in step 3 to 4.

If a = b then a^2 - b^2 = ab - b^2 is the same thing as saying 0 = 0. I think you are done at that point.

[Happy Monkey]

Originally Posted by Beestie

If a = b then a^2 - b^2 = ab - b^2 is the same thing as saying 0 = 0. I think you are done at that point.

No. 0=0 is OK, just like 1=1 is OK in step one. You just can't divide by zero.